ymmv but we had a lot of problems with extreme slowness and downtime when using parse, it made development a bear and we were only using it for some testing. We wouldn't use it in production after our experience.
I think mileage definitely varies! I use Parse on a large app in production (100,000+ active users) and haven't experienced any downtime or slowness. Although perhaps my use-case is different to yours. You should try getting in touch with the Parse guys, I've found them very helpful and responsive. Just thought I'd offer the other side of the coin.
